For example, if you were casting Serra Angel, which costs, you could tap three basic lands of any type to pay plus two Plains to pay.
To cast a spell, you must pay its mana cost (located in the upper right corner of the card) by tapping lands (or other permanents) to make the amount and type of mana which that spell requires. As your turn begins, untap your tapped cards so you can use them again. When a permanent is tapped, you can’t tap it again until it’s been untapped (turned back upright). You do this when you use a land to make mana, when you attack with a creature, or when you activate an ability that has the symbol as part of its cost ( means 'tap this permanent'). To tap a card is to turn it sideways to show that it has been used for the turn. This section describes the actions you'll take during a game, including tapping your cards, casting spells, and attacking/blocking with creatures in combat.
